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1

Oedema

An abnormal increase in interstitial fluid

2

Causes of Oedema

Increased hydrostatic pressure
Salt and H20 retention
Reduced plasma oncotic pressure
Inflammation
Lymphatic obstruction

3

Generalised Oedema

Fluid in serous cavities >5L (pleural, pericardial, peritoneal)

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3 Causes of generalised Oedema

Congestive heart failure
Hypoproteinaemia (low protein content)
Nutritional oedema

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Localised Oedema

Pulmonary and cerebral oedema

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4 Causes of localised oedema

Left heart failure
Inflammation
Venous hypertension
Lymphatic obstruction

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Pulmonary oedema

Normally plasma oncotic pressure is > hydrostatic pressure in pulmonary capillaries
Left heart failure increases hydrostatic pressure in pulmonary capillary bed
Fluid accumulates 1st in interstitial space and then eventually spills into alveolar spaces

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Main symptom of pulmonary oedema

Breathlessness (worse when lying flat)

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2 Causes of Cerebral Oedema

Vasogenic: Increased permeability of capillaries and venules
Cytotoxic: Derangement of sodium-potassium membrane pump e.g. ischaemic strokes

10

Thrombosis

Abnormal blood clot formation in the circulatory system

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3 Causes of Thrombosis

Endothelial injury
Stasis or turbulent blood flow
Blood hyper coagulability

12

What are the Primary causes of hypercoaguability?

Genetic:
Factor V mutation
Protein C deficiency

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What are the Secondary causes of hypercoaguability?

Acquired:
Obesity
Cancer
Stasis
Age
Use of oral contraceptive pill

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Venous thrombi mainly form in...

Deep leg veins

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2 Key contributory factors to venous thrombi

Stasis
Hypercoaguablilty

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Most important potential complication of venous thrombi

Pulmonary embolism

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What does narrowing of artery by thrombus cause?

Ischaemia of tissue supplied by artery

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What does complete blockage of artery by thrombus cause?

Infarction of tissue supplied by artery

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4 Fates of Thrombi

Propagation
Embolisation
Dissolution
Organisation and re-canalisation

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Thrombi come to clinical attention when they

Obstruct arteries or veins
Embolise

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Embolus

abnormal material within circulatory system that is carried in blood to a site distant from its point of origin

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Rare types of embolic material

Air
Fat
Amniotic fluid
Tumour

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Infarct

An area of ischemic necrosis caused by occlusion of arterial supply or venous drainage

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Red Infarct

Result of Venous occlusion
Often in loose tissue with dual circulation e.g. Lung

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White Infarct

Result of Arterial occlusion
Often in solid organs e.g. Spleen, Kidney

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Pulmonary thromboembolism:
What does emboli lodging in a major pulmonary artery cause?

Instantaneous death

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Pulmonary thromboembolism:
What does emboli lodging in medium sized arteries present with?

Breathlessness

28

Pulmonary thromboembolism:
What does emboli lodging in small arteries cause?

Subtle symptoms of breathlessness, chest pain and dizziness

29

Haemorrhage

Extravasation of blood due to vessel rupture

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What are the causes of Haemorrhage?

Trauma
Intrinsic disease of a vessel